Prevalence
The published estimates of the prevalence of insomnia vary considerably, ranging from 10-38%63. Research in the UK, has indicated that insomnia is thought to affect about one third of the general population55 whereas two US-based cross-sectional studies estimated the prevalence in people attending primary care to be between 10% and 50%585.
A systematic review has suggested that, while 30–48% of people reported the presence of insomnia symptoms and 8–18% reported dissatisfaction with sleep quality or quantity, only 6% met the criteria for a diagnosis of insomnia. Although one in twenty people are believed to present to healthcare professionals with insomnia-related symptoms, it is thought that many people with insomnia do not seek medical help63.
Prevalence has been reported to be higher in women and to increase with age. The age-related increase is believed to be multifactorial in origin and has been associated with changes in the time spent in different stages of sleep, increasing co-morbidities, and lifestyle related factors63.
Insomnia is a long-term disorder with about 75% of patients reporting symptoms lasting at least a year. The course of insomnia is more likely to be persistent in those with more severe insomnia, particularly in women and in older adults97.
What is known about the prevalence of insomnia97
- Estimates of prevalence of insomnia vary according to the definition used
- Prevalence of symptoms varies with age, with increase of nocturnal awakenings but decrease in complaints of non-restorative sleep as people get older
- Prevalence is between 1.5 and 2 times higher in women than in men
- Insomnia is a long-term disorder; many people have had insomnia for more than 2 years
- Approximately half of all diagnosed insomnia is related to a psychiatric disorder
